Revert all of my commits that devirtualized the Decl hierarchy, which
lead to a serious slowdown (4%) on parsing of Cocoa.h. This memory
optimization should be revisited later, when we have time to look at
the generated code.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126033 91177308-0d34-0410-b5e6-96231b3b80d8
9 files changed